It is a burnt mound, a type of site found scattered across Ireland and Britain, generally understood to represent the remains of ancient cooking or industrial activity. The typical interpretation is that stones were heated in fire, dropped into a water-filled trough to bring the contents to a boil, then discarded in a growing heap once they cracked and became useless. Over centuries, those discarded stones accumulated into the mound we see today.

This particular example measures twelve metres north to south, ten metres east to west, and rises to about 1.2 metres in height. A shallow trough, the functional hollow where the actual heating took place, opens to the west and encloses an area of roughly 4.5 metres by 3 metres. A small stream runs about ten metres to the south, which would have supplied the water essential to the whole operation. The site was recorded during a survey of the Lee Valley area carried out in 1996 and 1997, and the surrounding field shows little sign of recent agricultural activity, which may in part explain why the mound has survived in reasonable condition. The reeds and grass that now cover it are not incidental; wetland vegetation tends to colonise these sites precisely because the disturbed, moisture-retaining ground suits it.